I'd like to know whether anyone else has experienced the same problem with KDE 3.5.5:

When I try to start a konsole by clicking on the Konsole icon in the
taskbar, the konsole wiondow opens, immediately follwed by a popup that
gives the message: Konsole is unable to open a PTY (pseudo teletype).
It is likely that this is due to an incorrect configuration of the PTY
devices. Konsole needs to have read/write access to the PTY devices.

When I click on the popup's OK button, the konsole disappears.

This happens irrespective of whether I'm logged in as a normal user or as root.